If you look towards the front of the motor you will see the generator on a similar angle to the front cylinder. They called these 45's, "3 cylinder" Harleys. I think 1931 was the last year for that configuration. If you really want to know all about it, ask Red Fred, our new technical director. He loves Harley Davidsons.

Actually, it began as a derisive term coined by rival Indian riders when the new Harley model "DL" Sidevalve 45 cubic inch twins were introduced in 1929. They're the bikes the three teenage H-D heirs are pictured upon in front of Dudley Perkins' dealership in San Francisco in 1929, a famous photo taken when they were on their promotional tour, introducing the new model.
The bike was Harley's attempt to answer Indian's success with the 45 c.i. "Scout" of the era. And the always-thrifty Harley-Davidson founders were trying to save money while building a high-performance 45, by putting the 45 Flathead motor in what had been their 30.50 Singles' frame (notice the straight front downtube). That frame allowed them to shoehorn in the 45 twin motor, but with no room for a generator across the front of the crankcase, only a jackshaft. On the left end of the jackshaft were a pair of bevel gears that drove the vertical generator.
The bevel gears were the achilles' heel of the set up. Though provided with their own oil supply, soon the constant throttle action, up and down, beat the bevel gears to death from both directions in the DLs (1929, '30 and '31). Lots of them came back to dealers for repairs.
You'll notice the 1932-36 RLs have an "S" bend in the front downtube, to make room for a horizontal generator. No more "Three Cylinder Harley."

It's interesting that the bike in the pictures is finished in the 1933 paint scheme, when the vertical generator 45s were produced only 1929-31.

People did that a LOT in the Thirties. "No one" had any money for a new bike, or not a often as they'd have liked, during the Great Depression, so a cheap way to keep-up-with-the-Joneses was to apply the current year's paint job to your aging mount, or so it seems from the number of such repaints you see in old photos.
Cale, an old friend of mine (1912-2002), confirmed to me that it was a common practice when he rode in those years. "Riders did that a lot," he said. "Cheaper than a whole new bike!"
He was one of a kind, a co-founder of Seaboard Chapter. I still rode with him, me on my '37UL and he on his '47EL in the 1980s. I miss him.